Stingray,
I'd just use an 8-way for Q-Bert.
If you get one like the Happs Competition, etc... that REALLY hits the diagonals hard, I think it's actually a better option.
The unrestricted 8-way feels like a rotated 4-way w/restrictor.
You can program the 8-way for "this game only" to use:
Joystick Direction=Game Direction
Up-Left=Left
Up-Right=Up
Down-Right=Right
Down-Left=Down
To do this, just go to the "Inputs for this game only" screen, hit enter on each of the directions, and then push the stick to the appropriate corner.
Done correctly, you should see (Left UpLeft) for the input for that direction.
Go back to the game, and you should have a GREAT Q-Bert Stick.